Merge remote-tracking branch 'upstream/pr/1203'

@ploxiln:

  "It seems like a bit of refactoring might be able to clean this code
up a bit, but it's a bit tricky because of the varied tricky usage of
chain structs, so this initial version has minimal changes ... "

* upstream/pr/1203:
  buffer: do not round up allocation for reference-type chain objects